Variable ratio manual controller for aircraft



oa. 1o, 1939.

s. J. ZAND 2,175,584

VARIABLE RATIO MANUAL CONTROLLER- FOR AIRCRAFT original Filed May 21,1935 Patented Oct. 10, 1939 PATENT OFFICE vAaIALE RATIO MANUALCONTROLLER Fon AIRCRAFT Stephen J. Zand, Forest Hills, N. Y., assignorto Sperry Gyroscope Company, Inc., Brooklyn, N. Y., a corporation of NewYork Application May 21, 1935, Serial No. 22,554 Renewed September 25,1937 8 Claims.

This-invention relates to the control of aircraft, especially of highspeed craft in which auxiliary devices are usually provided for reducedspeeds, as when landing. The amount of angular displacement of anairplane control stick or wheel is, roughly, inversely proportional tothe speed of the airplane. Where,' as in modern planes, the ratiobetween the landing speed and top speed is great, the control of theairplane under the two `conditions named becomes difllcult, since if the{control'is built to have sufcient movement at lowA speeds, it becomesover-sensitive at high' speeds. and if built to operate normally at highspeed, it will not control the airplane eilciently #at slow or landingspeeds. The dual speed range is usually obtained by the use of flaps,usually lo- ;cated at the rear and under the wing surface so as toincrease the camber of the air foil, thus increasing both the drag andlift to greatly lower the speed of the craft and at the same timemaintain it in the air.

According to my invention, I provide an automatic means which changesthe ratio of movement between the control sticks and the several`control surfaces or rudders of the plane (i. e., the elevating, steeringand aileron rudders, or at least some of the same) in accordance withthe position of the flap, so that when the flap is not in use, a minimummovement of the control surfaces is secured, while when the flap orspoiler l is down, a maximum movement is secured for a given movement ofthe control stick. In other words, I decrease the relative movement ofthe control surfaces as the craft passes from its low 85 speed range toits high speed range, and vice versa. Y

Referring to the drawing, the single i'lgure is a `diagram showing howmy invention may be applied to the three controls of an airplane, inele- 4o vation, laterally and in azimuth. The steering rudder is shownat R and is normally controlled from a foot pedal l; the elevator is atE and is controlled by forward and backward movement of the controlstick 2; and the ailerons, represented 4B at A. are controlled by therotation of wheel 3 on stick 2, these controls being intended torepresent any conventional manual control system for airplanes. Betweeneach manually operated part and its control surface, I place a variablethrow device 4, 4', 4". by which the ratio of movement of the rudder tothe movement of the control device is/varied. This may take the form ofa block pivoted on a shaft 5 for oscillation, and having rotatablymounted thereon a threaded shaft 6 i which is shown as having threads atthe opposite 8 are secured, which are connected to the h rudder R.

Block 4 is sh'own as oscillated from the foot 5 pedals i by cables 9 and9'. In order t9 take up the slack in the cables 8, 8' and maintain thesame under constant tension, I provide a second reversely threaded shaftI0 on which are mounted, at each end, nuts Il and il'. By rotatingshafts 10 6 and l0 in opposite directions, the nuts Il and Il will movein the opposite direction from the nuts 1 and 1 to maintain constanttension of the cables. V7

Beth of shafts s and lu are preferably rotated 15 automatically from themeans for adjusting the ilap F which controls the eiective camber oftheair foil. In this case the flap is shown as power actuated from anelectric motor l 2, the operation of which is controlled by a switch i3yon the 'air- 20 craft panel. The motor I2 is shown'as operating,through' a pinion I4 and gear I5, a drum I6 which turns a similar drumil provided with internal threads and operating to screw up and downthreaded shaft I8. Theraising and low- 25 ering of said shaft controlsthe position of flap F through any suitable meav such as the link I9 andlever 20 which turns the flap about pivot 2|, usually placed underneathand near the rear of the main air foil or wing, represented dia- 30grammatically at 22. The flap controlling means actuates both shafts 6and I0 through any suitable gearing. As shown, a bevel gear 23 ismounted on shaft 24 of pinion l5 and turns a pair'of bevel gears 25'and26. Shaft 24 also eX- 35 tends through the gear box 28 and is coupled toa flexible shaft 29 connected with the shaft 6. 'I'he shaft dIll islikewise turned through flexible shaft 30 driven from a gear 3l on shaft24 and a pinion 32, the shaft so driving the shaft lo 40 through pinion33 and gear 34 on shaft l0.

The controls for the ailerons and elevator are similar and are alsoactuated from the same gear box 28. As shown, the elevator control 2 isconnected to the oscillatory member 4 through cross cables 35 and 35',and the threaded shaft 6' of member 4 is turned through a flexible shaft29 driven from the bevel gear 25, while the threaded shaft I0' is driventhrough suitable gearing 40 50 and flexible shaft 130' from the samebevel gear. SAi/milarlylevel gear 26 drives a threaded shaft ofoscillatory member 4", which is connected by cables 36 and 3.6' tobeactuated from the tu'rning of handle I. In this case, flexible shafts29" and 30" connect the shafts 6 and I0", respectively, through bevelgear 26.

As many changes could be made in the above construction and manyapparently widely different embodiments of this invention could be madewithout departing from the scope thereof, it is intended that all mattercontained in the above description or shown in the accompanying drawingshall be interpreted as illustrative and not in a limiting sense.

Having described my invention, what I claim and desire to secure byLetters Patent is:

1. The combination with an aircraft having an auxiliary wing device .forreducing landing speed, the ordinary control surfaces and the manualcontrols therefor, of means between at least some of said controls andthe saidsurfaces for varying their relative ratios of movement, andmeans connecting said auxiliary wing device and said ratio varying meansfor causing' increased throw of said surfaces when landing.

2. In an aircraft control system having control surfaces and manualcontrols therefor, an auxiliary device for increasing the effectivecamber of the air foil for reduced landing speed, and means forincreasing the throw of said surfaces for a given movement of saidmanual controls brought into action by operation of Said auxiliarydevice to increase the effective camber of the air foil.

3. The combination with an aircraft having an auxiliary wing device forreducing landing speed, the ordinary control surfaces and the manualcontrols therefor, of means between at least some of said controls andthe said surfaces 4for varying their relative ratios of movement, meansconnecting said auxiliary wing device and said means for causingincreased throw of said surfaces when landing, and means for maintainingthe connections between said controls and said surfaces taut at alltimes.

4. In an aircraft control system having con trol surfaces and manualcontrols therefor, an auxiliary device for varying the effective camberof the air foil for correspondingly varying the minimum flying speed,and means for varying the throw of said surfaces for a given movement ofsaid manual controls in accordance with the extent of movement of saidauxiliary device, whereby, as the camber of the air foil is increased,the throw of said surface is increased. g y

5. The combination with an aircraft having a flapfor reducing landingspeed, the ordinary control "surfaces and controls therefor, of meansbetween at least one of said controls and its control surface forvarying their relative ratio of movement, and means for connecting saidiiap and said ratio varying means for causing increased throw of saidcontrol surface when said flap is moved to reduce landing speed.

6. The combination with an aircraft having a flap for varying theaircraft's wing camber to vary the crafts landing speed, the ordinarycontrol surfaces and controls therefor, 0f variable transmission meansbetween at least one of said controls and its control surface forvarying their relative ratio of movement, and additional transmissionmeans for connecting said flap and said variable transmission means forcausing a progressive increase in the relative throw of said controlsurface with respect to its control as said flap is moved to reducelanding speed.

7. The combination with an aircraft having means for greatly varyingflying speed and wing lift of the craft, the ordinary control surfacesand the controls therefor, of means between at least some of saidcontrols and the said surfaces for varying their relative ratios ofmovement, and means connecting said first named means and said ratiovarying means for causing increased throw of said surfaces at slowspeeds.

8. The combination with an aircraft having wing flaps for varying thecrafts normal speed and wing lift, the ordinary control surfaces andcontrols therefor, of variable transmission means between at least oneof said controls and its control surface for varying their relativeratio of movement, and additional transmission means for connecting saidwing flaps and said variable transmission means for causing aprogressive increase in the relative throw of said control surface withrespect to its control as said wing flaps reduce the crafts speed.

STEPHEN J. ZAND.

